The accepted narrative on medical imaging says imaging rates peaked in the mid-2000s, but tailed off and began to decline more recently. The percentage of annual medical visits made by Medicare-aged patients that resulted in imaging, however, has been in steady decline since 2003, according to a study published in the July issue of the Journal of the American College of Radiology.

While most analyses of medical imaging trends have focused on frequency of services or spending in dollars, a different story emerges when the focus of analysis shifts to the proportion of encounters that result in medical imaging, explained Martey S. Dodoo, PhD, and colleagues from the Harvey L. Neiman Health Policy Institute, Reston, Virginia.

“Despite early growth and then more recent declines in average Medicare spending per enrollee since 2003, the percentage of patient encounters resulting in medical imaging has significantly and consistently declined nationwide,” wrote the authors. “Spending alone is thus an incomplete measure of changes in the role and utilization of medical imaging in overall patient care.”

Dodoo and colleagues discovered this previously hidden trend in imaging utilization by examining household component events data for patients aged 65 years and older from the Medical Expenditure Panel Survey (MEPS) for 2003 to 2010. This provided detailed utilization data on a large, nationally representative sample, with each participant being interviewed five different times. They compared this information to utilization and spending rates from Medicare Part B claims data from 2003 to 2011.

“When describing trends in imaging utilization, researchers and policymakers have traditionally focused on service units, relative value units, allowed charges, and payments as metrics of utilization,” wrote the authors. “Although these accurately capture the frequency of performed services and associated resource consumption and spending in selected populations, they neglect to consider the complete role of imaging in the context of actual patient care.”

True to the traditional method of analysis, Dodoo and colleagues found annual health spending and Medicare payments for imaging in the Medicare-aged population grew from $294 to $418 per enrollee from 2003 to 2006, then declined to $390 per enrollee by 2011.

The MEPS data, however, showed a consistent downward trend in the proportion of medical visits resulting in imaging, from 12.8 percent in 2003 to 10.6 percent in 2011, reported the authors.

In trying to explain the discrepancy between spending rates and imaging per encounter, Dodoo and colleagues speculated there could have been an increase in physician clinical encounters, a decline in the absolute frequency of medical imaging, or both.

“As policymakers focus on medical imaging, a thoughtful analysis of payment policy influencing imaging utilization, and its role in concurrent and downstream patient care, will be critical to ensure appropriate patient access,” wrote the authors.